Rewrite and delabelize vertical border check. (Bug#5357) (Bug#9618)

* window.c (coordinates_in_window): Rewrite and delabelize
vertical border check.  (Bug#5357) (Bug#9618)

2 files changed, 35 insertions, 51 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 79503c147e3..2c72e97b7f7 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2011-10-15  Martin Rudalics  <rudalics@gmx.at>
+
+        * window.c (coordinates_in_window): Rewrite and delabelize
+        vertical border check.  (Bug#5357) (Bug#9618)
+
 2011-10-14  Stefan Monnier  <monnier@iro.umontreal.ca>
 
         * xterm.c (frame_highlight, frame_unhighlight): Ignore unexplained
diff --git a/src/window.c b/src/window.c
index ba06779846a..c3b4384137d 100644
--- a/src/window.c
+++ b/src/window.c
@@ -919,22 +919,45 @@ static enum window_part
 coordinates_in_window (register struct window *w, int x, int y)
 {
   struct frame *f = XFRAME (WINDOW_FRAME (w));
-  int left_x, right_x;
   enum window_part part;
   int ux = FRAME_COLUMN_WIDTH (f);
-  int x0 = WINDOW_LEFT_EDGE_X (w);
-  int x1 = WINDOW_RIGHT_EDGE_X (w);
+  int left_x = WINDOW_LEFT_EDGE_X (w);
+  int right_x = WINDOW_RIGHT_EDGE_X (w);
+  int top_y = WINDOW_TOP_EDGE_Y (w);
+  int bottom_y = WINDOW_BOTTOM_EDGE_Y (w);
   /* The width of the area where the vertical line can be dragged.
      (Between mode lines for instance.  */
   int grabbable_width = ux;
   int lmargin_width, rmargin_width, text_left, text_right;
-  int top_y = WINDOW_TOP_EDGE_Y (w);
-  int bottom_y = WINDOW_BOTTOM_EDGE_Y (w);
 
-  /* Outside any interesting row?  */
-  if (y < top_y || y >= bottom_y)
+  /* Outside any interesting row or column?  */
+  if (y < top_y || y >= bottom_y || x < left_x || x >= right_x)
     return ON_NOTHING;
 
+  /* On the mode line or header line?   */
+  if ((WINDOW_WANTS_MODELINE_P (w)
+       && y >= bottom_y - CURRENT_MODE_LINE_HEIGHT (w)
+       && (part = ON_MODE_LINE))
+      || (WINDOW_WANTS_HEADER_LINE_P (w)
+          && y < top_y + CURRENT_HEADER_LINE_HEIGHT (w)
+          && (part = ON_HEADER_LINE)))
+    {
+      /* If it's under/over the scroll bar portion of the mode/header
+         line, say it's on the vertical line.  That's to be able to
+         resize windows horizontally in case we're using toolkit scroll
+         bars.  Note: If scrollbars are on the left, the window that
+         must be eventually resized is that on the left of WINDOW.  */
+      if ((WINDOW_HAS_VERTICAL_SCROLL_BAR_ON_LEFT (w)
+           && !WINDOW_LEFTMOST_P (w)
+           && eabs (x - left_x) < grabbable_width)
+          || (!WINDOW_HAS_VERTICAL_SCROLL_BAR_ON_LEFT (w)
+              && !WINDOW_RIGHTMOST_P (w)
+              && eabs (x - right_x) < grabbable_width))
+        return ON_VERTICAL_BORDER;
+      else
+        return part;
+    }
+
   /* In what's below, we subtract 1 when computing right_x because we
      want the rightmost pixel, which is given by left_pixel+width-1.  */
   if (w->pseudo_window_p)
@@ -948,50 +971,6 @@ coordinates_in_window (register struct window *w, int x, int y)
       right_x = WINDOW_BOX_RIGHT_EDGE_X (w) - 1;
     }
 
-  /* On the mode line or header line?  If it's near the start of
-     the mode or header line of window that's has a horizontal
-     sibling, say it's on the vertical line.  That's to be able
-     to resize windows horizontally in case we're using toolkit
-     scroll bars.  */
-
-  if (WINDOW_WANTS_MODELINE_P (w)
-      && y >= bottom_y - CURRENT_MODE_LINE_HEIGHT (w))
-    {
-      part = ON_MODE_LINE;
-
-    header_vertical_border_check:
-      /* We're somewhere on the mode line.  We consider the place
-         between mode lines of horizontally adjacent mode lines
-         as the vertical border.  If scroll bars on the left,
-         return the right window.  */
-      if ((WINDOW_HAS_VERTICAL_SCROLL_BAR_ON_LEFT (w)
-           || WINDOW_RIGHTMOST_P (w))
-          && !WINDOW_LEFTMOST_P (w)
-          && eabs (x - x0) < grabbable_width)
-        return ON_VERTICAL_BORDER;
-
-      /* Make sure we're not at the rightmost position of a
-         mode-/header-line and there's yet another window on the
-         right.  (Bug#1372)  */
-      else if ((WINDOW_RIGHTMOST_P (w) || x < x1)
-               && eabs (x - x1) < grabbable_width)
-        return ON_VERTICAL_BORDER;
-
-      if (x < x0 || x >= x1)
-        return ON_NOTHING;
-
-      return part;
-    }
-
-  if (WINDOW_WANTS_HEADER_LINE_P (w)
-      && y < top_y + CURRENT_HEADER_LINE_HEIGHT (w))
-    {
-      part = ON_HEADER_LINE;
-      goto header_vertical_border_check;
-    }
-
-  if (x < x0 || x >= x1) return ON_NOTHING;
-
   /* Outside any interesting column?  */
   if (x < left_x || x > right_x)
     return ON_SCROLL_BAR;